If you ever figure it out let me know.
I imagine it is simply a cyclic sort of thing. Open societies provide rungs upon which cliques can pull themselves up to the point that they are able to overcome the myopic complacency of the people who have spent their lives steeped in liberty, and thus establish a strict, shall we say fascistic, order. Regular folk, even the ones who are steadfastly maintaining the open society, simply do not believe that it can roll over in a moment. But social orders do not change gradually, the nexus absolutely has to be climactic in order to succeed.
Similarly, a strict, oppressive social order is vulnerable to rolling over into a different, more open society, which also has to commence abruptly. Oppression breeds resentment, which eventually festers to the point of breaking out into an overthrow. Even a dictatorship has to accede to the needs of the citizens, and a wise leader will try to give and take to keep the resentment below the threshold of hazard, but leaders change, and eventually a fool will be at the helm. This is compounded by the insularity of the inner circle, which is bound to lose sight of the critical issues.
So, it is like the tide, going out, coming in, going out again. There is possibly a formula that can balance an open system in a way that prevents or aborts the rise of cliquish power, but the problem is described in a song by The Who, "…
Meet the new boss, Same as the old boss …" The very fact that social change relies on catharsis makes establishing a sustainable social replacement incredibly difficult. As I often quip,
If you find yourself going around in circles, maybe you are having too many revolutions.
I think I got some or most of these ideas from reading
The Prince by Nicolo Macchiavelli. I highly recommend it, especially the version that has a preface longer than the text, giving a history lesson covering his times.